The present disclosure herein relates to an apparatus and method for manufacturing a semiconductor substrate, and more particularly, to an apparatus and method for drying a substrate.
Generally, a semiconductor device is manufactured by performing various processes such as a photo process, an etching process, an ion implantation process, and a deposition process on a substrate such as a silicon wafer.
In this case, various kinds of foreign substances such as particles, organic contaminants, and metallic impurities occur during the processes. Since these foreign substances cause a defect of a substrate and act as a factor that has a direct effect on the performance and the yield of the semiconductor device, a cleaning process for removing the foreign substances is necessarily carried out during the manufacturing process of the semiconductor device.
The cleaning process includes a chemical treatment process that removes contaminants on a substrate with a chemical, a wet cleaning process that removes the chemical remaining on the substrate with pure water, and a drying process that removes the pure water remaining on the substrate by supplying a drying fluid.
In the past, the drying process was performed by supplying a heated nitrogen gas onto a substrate on which pure water remains. However, as the line width of a pattern formed on a substrate becomes narrow and the aspect ratio increases, it becomes difficult to remove pure water between patterns. For this, in recent years, pure water is substituted by a liquid organic solvent such as isopropyl alcohol having a higher volatility and a lower surface tension than pure water, and then a heated nitrogen gas is supplied to dry the substrate.
However, since the non-polar organic solvent and the polar pure water are not easily mixed, a large amount of liquid organic solvent needs to be supply for a long time to substitute pure water with the liquid organic solvent.
In a typical drying process, pure water has been substituted by organic solvent such as isopropyl alcohol having a relatively low surface tension, and then has been evaporated.
However, in this drying method, a pattern collapse is still caused regarding a semiconductor device including a fine circuit pattern in which the line width is equal to or less than about 30 nm even though the organic solvent is used. In order to overcome this limitation, a typical drying process is recently being replaced with a supercritical drying process.